In a snowy valley in central Japan, a farmhouse could keep silkworms up in its roof and, in pits beneath the floor, a slow brew that would become an ingredient of gunpowder. The family lived on the floor in between.
Three villages on the Sho River
The village of Ogimachi, in Shirakawa-go, sits on a level terrace on the east bank of the Sho River, which runs north through a narrow, deep mountain valley toward the Sea of Japan. Ogimachi is the largest of the three villages on the list, with more than a hundred gassho buildings, about sixty of them main houses, and people still live in many of them. Gassho means hands pressed together in prayer, and the steep roofs resemble them. Each roof rises at about sixty degrees, which helps heavy snow slide off; an ordinary Japanese farmhouse roof is pitched at under forty-five. Paper windows high in the gable ends light floors hidden inside the roof.
Downriver, in Toyama Prefecture, lie the two Gokayama villages: Ainokura, with about twenty gassho houses, and Suganuma, the smallest, with nine. This is among the snowiest country in Japan, with two to three metres of snow in a heavy winter, and until the 1950s the valley had very little contact with the outside world. Through the Edo period, Gokayama belonged to the Kaga domain.
Paper, gunpowder and silk
Here the terrain made rice farming largely unsuccessful, so families found income inside their own houses. One source was washi, Japanese paper, made from the fibre of the paper mulberry that grew naturally in the area, with the ground floor serving as the workshop.
By the late 1600s, families were also making saltpeter, an ingredient of gunpowder. They dug pits under the floor around the sunken hearth and filled them with soil and plants such as mugwort, mixed with waste, then left the mixture to decompose for several years until it yielded saltpeter. Because it went into weapons, production was tightly controlled, and Gokayama's saltpeter went to the Kaga domain. The trade ended in the Meiji era, when cheaper imported saltpeter arrived.
Silk changed the shape of the house. Late in the Edo period, raising silkworms became the area's most important industry. Silkworms needed space for their beds and for storing the mulberry leaves they ate, picked from trees grown nearby, and the answer was the roof. Inside the steep thatch, families laid floors at two to four levels. Heat and smoke from the hearth rose through a slatted ceiling, keeping the attic warm and dry. Most gassho houses standing today were built in the 1800s and early 1900s, as silk grew. One of the largest, the Iwase house in Gokayama, has five storeys and stands more than fourteen metres tall.
One roof in a day
Professional carpenters built the frame of the ground floor; the villagers built the roof themselves. It starts as pairs of thick logs leaned together into a triangle and set on the beams of the house below, without being fixed to them, so the roof can flex under heavy snow. The roof uses no nails. The joints are tied with straw rope and with neso, made from young witch hazel branches. Because a frame of leaning triangles is weak sideways, diagonal bracing runs across the plane of the roof to make it rigid, a method Japan's nomination says is found nowhere else in the country.
Over the frame goes kaya, thatch of mountain grasses such as miscanthus, harvested every year and stored, because a roof needs a huge amount of it. About every twenty to thirty years the old thatch is removed and the whole roof replaced. That is where yui comes in, the custom of mutual help. The owner asks the neighbours, who belong to a kumi, a group of households that shares village tasks. Up to about two hundred people, from elders to the young, turn out, some thatching on the roof while others haul grass up from the ground, and the job is done in a day. A long wooden needle carries rope through the thatch to fasten it, and a wooden paddle beats and packs the stalks. Afterwards, smoke from the hearth drifts up into the thatch, keeping insects out and the grass dry. Village records list who took part and in what role, and the household that was helped later helps others in return.
Why it's on the list
UNESCO inscribed the three villages in 1995. Under its first criterion, they are outstanding examples of traditional settlements, well adapted to their environment and to their social and economic purpose, and UNESCO's description calls the large, steep-roofed houses the only examples of their kind in Japan. Under the second, the villages' social structure, which their layouts express, survived the economic changes Japan went through after 1950. The record also notes that the settlements have existed since the eleventh century, and credits the residents' customary collaboration with keeping the thatched roofs in good condition.
It is easy to picture gassho houses once standing all over Japan. Japan's nomination counts about 1,860 at their peak in the late nineteenth century, when the country had about 5.5 million farmhouses. That made them roughly three in every ten thousand, and all of them belonged to this one mountain region.
In a snowy valley in central Japan, a farmhouse could hold silkworms up in its roof and, in pits beneath the floorboards, a slow brew that would become an ingredient of gunpowder. The family lived in the rooms between.
This is Ours to Keep. I'm Mira, and today: the Historic Villages of Shirakawa-go and Gokayama. I'm an AI voice; the facts come from official records and checked sources.
A village on a river terrace
The village of Ogimachi sits on a flat terrace on the east bank of the Sho River. The river runs north through a narrow mountain valley, toward the Sea of Japan. Ogimachi is the largest of the three villages on the list. It has more than a hundred gassho buildings, and about sixty of them are main houses. People still live in many of them. Gassho means hands pressed together in prayer, and seen from the end, each steep roof looks like a pair of hands joined that way. Here, as in the other two villages, houses on sloping ground sit on terraces held up by stone walls. Storehouses stand a little apart from the houses, so that a fire in one building is less likely to spread. Small fields and rice paddies sit between and around them.
Walk through Ogimachi and you notice that most of the houses face the same way. Their ridges run north to south, so the wide slopes of thatch face east and west. Part of the reason is the wind that funnels along the valley. Each roof rises at about sixty degrees, and the steep pitch helps heavy snow slide off. A typical Japanese farmhouse roof is pitched at less than forty-five. High in the triangular gable ends are windows covered with paper. They let light into floors you can't see from outside, because they are hidden inside the roof.
Downriver, across the border in Toyama Prefecture, are the two Gokayama villages. Ainokura has about twenty gassho houses. Suganuma, the smallest, has nine. The houses differ a little from Ogimachi's. In Gokayama the main entrance is usually under the gable end, while in Ogimachi it is usually on the long side. This is some of the snowiest country in Japan. In a heavy winter, two to three metres of snow can fall here. Until the 1950s, the valley had very little contact with the outside world.
In the Edo period, from the late 1600s, Shirakawa-go was ruled directly by the shogun's government. Gokayama belonged to the Kaga domain. On both sides of the border, the land was too steep for much rice. Families needed another way to earn a living, and they found it inside their own houses.
Work under the thatch
One source of income was paper. People made washi, Japanese paper, from the bark of the paper mulberry, a shrub that grew wild in the valley. The ground floor of the house served as the workshop.
By the late 1600s, families were also making saltpeter, an ingredient of gunpowder. Under the floor of the house, around the sunken hearth, they dug deep pits. They filled them with soil and plants such as mugwort, mixed in waste, then left the mixture to break down for several years until it yielded saltpeter. Because it went into weapons, the trade was tightly controlled. In Gokayama, the saltpeter went to the Kaga domain. The trade ended in the Meiji era, when cheaper imported saltpeter arrived.
Silk changed the shape of the house. Late in the Edo period, raising silkworms became the valley's most important industry, and it stayed central to life here into the twentieth century. Silkworms need room. They need beds to feed on, and a great store of mulberry leaves to eat, picked from mulberry trees grown nearby. The answer was the roof. Inside the steep thatch, families laid floors at two to four levels and used them for the silkworms and their leaves. Those paper windows in the gables lit the work. Heat and smoke from the sunken hearth below rose through a ceiling of spaced slats, keeping the upper floors warm and dry.
Most of the gassho houses standing today were built in the 1800s and early 1900s, as the silk trade grew. One of the largest, the Iwase house in Gokayama, has five storeys and rises more than fourteen metres. Big houses held big households. In some villages, ten or more relatives once shared a single house, because farmland was scarce and every pair of hands was needed.
The German architect Bruno Taut spent about three years in Japan in the 1930s, studying its buildings. In 1935 he came to the valley to see these houses. He was struck by how rational they were, and he later wrote about them. Decades later, Japan's case for World Heritage listing cited his writing.
One roof in a day
Let's follow a single gassho roof, from the bare frame to the finished thatch. The house was a shared job. Professional carpenters built the frame of the ground floor. The villagers built the roof themselves. Thatching takes skill as well as a great deal of labour.
The roof starts as pairs of thick logs, leaned together into a triangle and set on the beams of the house below. The roof frame is not fixed to the walls. It rests on them, and that lets it give a little under heavy snow. Nothing up here is nailed. The joints are tied with straw rope and with neso, a binding made from young witch hazel branches.
A frame of leaning triangles is weak against sideways forces. So builders added long diagonal braces across the roof, turning each slope into a stiff panel. Japan's nomination to UNESCO says this bracing is found nowhere else in the country.
Over the frame goes the thatch, called kaya, made of mountain grasses such as miscanthus. Families cut it every year and stored it until a roof needed it, because a single roof takes a huge amount of grass. About every twenty to thirty years, the old thatch comes off and the whole roof is thatched again.
That is where yui comes in, the village custom of helping one another. The owner asks the neighbours for help. Neighbours here belong to a kumi, a group of nearby households that shares village chores. On the day, up to two hundred people can turn out, from elders to young people, and the job is done in a single day. Some work on the roof. Others haul the bundles of grass up from the ground. Because every generation takes part, the skills are passed down.
On the slope, workers set the bundles in place. A long wooden needle carries rope through the thatch to tie it to the frame. A wooden paddle beats the stalks flat and packs them tight.
After that, the hearth does its part. Smoke drifts up through the slatted floors and into the thatch, keeping insects out and the grass dry.
Village records list who came and what job each person did. The family that was helped returns the favour when another roof comes due.
Why it's on the list
So why is it on the list? UNESCO inscribed these three villages in 1995, under two criteria. The first is that they are outstanding examples of traditional settlements, closely fitted to their mountain setting and to the way people earned a living there. UNESCO's description calls the large, steep-roofed gassho houses the only examples of their kind in Japan.
The second criterion is about something harder to see. The social structure of these villages, which their layouts make visible, survived the sweeping economic changes Japan went through after 1950. So the villages hold both physical and living evidence of a long history. The number of gassho houses has fallen since the Second World War, but every one that remains is part of the site. The record adds that the settlements go back to the eleventh century, that the remaining houses still stand where they were built, and that the old roads and canals have changed little. It credits the residents' long habit of working together with keeping the thatched roofs in good condition. And because the houses follow a standard pattern, repairs involve very little guesswork.
The surprise
Here's the surprise. Shirakawa-go has become a picture of old rural Japan, so it's easy to assume houses like these once stood all over the country. They didn't. Japan's nomination to UNESCO counts fewer than two thousand gassho houses at their peak, in the late 1800s. At that time, Japan had roughly five and a half million farmhouses. That makes the gassho house about three in every ten thousand, and it belonged to this one mountain region. Even at their peak, they were rare.
Next week, we cross the Pacific to Peru, trading these snowy valleys for the high Andes and the people who keep Peru's traditions alive.
